The initial vision was to set up a building society that specialised in properties that conveyed an ecological benefit in terms of construction, use of land or lifestyle.

The idea first appeared at a Green Party Conference, following the experience of a Yorkshire solicitor, David Pedley, who had great difficulty in finding anyone willing to give him a mortgage on a property needing extensive renovation.

Ecology was founded by ten initial supporters who each invested £500, raising the £5,000 capital which was the minimum required to start a building society at that time.

This primary purpose is anchored in the memorandum of the society, which contains a requirement "to promote…ecological policies designed to promote or enhance the environment in accordance with the principles of sustainable development".

Sustainable development is defined as "Improving the quality of human life while living within the carrying capacity of supporting ecosystems".